Another interesting thing you could link back to this is zonulin. Zonulin doesn't just regulate intestinal permeability, but apparently also regulates the permeability of the blood brain barrier, therefore letting more nasties into the brain then normal! So I guess this is another way gut and brain go hand in hand.
There's a drug in trial phase of development designed to regulate this. Sigh. Shame its not ready yet. I most definitely have both intestinal permeability AND blood brain barrier permeability.